In current highly technological and highly economic lives, electric power is necessary for mechanics and electricity. However most of current power source for generating electric power is generated from charcoal, petroleum, natural gas, uranium, etc. These can not be reused and will be exhausted in near future. Moreover, these non-reused energy sources will pollute the environment and generate ecological crisis. However solar energy is a clean energy which generates no pollution to the environment and has no ecological crisis. Thus solar energy has become a main trend of an energy source for substituting the conventional energy sources.